Hyperhomocysteinemia and its relationship to cardiovascular disease in ESRD: influence of hypoalbuminemia, malnutrition, inflammation, and diabetes mellitus

Associations between the conicity index and kidney stone disease prevalence and mortality in American adults

Kidney Stone Disease (KSD) is a prevalent urological condition, while abdominal obesity is on the rise globally. The conicity index, measuring body fat distribution, is crucial but under-researched in its relation to KSD and all-cause mortality. This study, using data from 59,842 participants in the NHANES (2007-2018), calculated the conicity index from waist circumference, height, and weight. Logistic regression and Cox models revealed a significant positive correlation: each 0.1 unit increase in the conicity index was linked to a 23% rise in KSD odds (OR: 1.23, 95% CI: 1.14, 1.35) and higher predictive ability compared to traditional measures (AUC = 0.619). In KSD patients, this increase corresponded to a 44% higher risk of all-cause mortality (HR: 1.44, 95% CI: 1.14, 1.82), and in non-KSD patients, a 53% increase (HR: 1.53, 95% CI: 1.37, 1.70). Serum albumin and Red Cell Distribution Width (RDW) partially mediated these relationships. Addressing central obesity could significantly lower the risks of KSD and mortality.

A predictive model based on serum bicarbonate for cardiovascular events after initiation of peritoneal dialysis

BACKGROUND

The risk of cardiovascular events (CVEs) in peritoneal dialysis (PD) patients is high, but varies widely among individuals. Metabolic acidosis is prevalent in PD patients and may be involved in the development of CVEs. The aim of the study was to evaluate serum bicarbonate as a risk factor and derive a model of new CVE.

METHODS

A predictive model was established by performing an observational study in 187 PD patients obtained from the First Affiliated Hospital of Anhui Medical University. The variables were extracted using least absolute shrinkage and selection operator (LASSO) regression, and the modeling was developed using multivariable Cox regression.

RESULTS

Left ventricular hypertrophy (HR = 1.965, 95%CI 1.086-3.557) and history of CVEs (HR = 2.435, 95%CI 1.342-4.49) were risk parameters for a new CVE. Serum albumin (HR = 0.924, 95%CI 0.864-0.989) and bicarbonate levels (HR = 0.817, 95%CI 0.689-0.969) were protective parameters, in which the risk of CVEs was reduced by 7.6% and 18.3% for each 1-unit increase in serum albumin (g/L) and bicarbonate (mmol/L) levels, respectively. A nomogram based on the above predictive indicators was proposed with a C-statistic of 0.806, indicating good discrimination. Moreover, it successfully stratified patients into low-, intermediate-, and high-risk groups.

CONCLUSIONS

We performed a risk prediction model for the development of CVEs in patients with PD, which may help physicians to evaluate the risk of new CVEs and provide a scientific basis for further interventions. Further studies are needed to externally validate current risk models before clinical application.

Hyperhomocysteinemia and Disease-Is 10 μmol/L a Suitable New Threshold Limit?

Hyperhomocysteinemia (HHcy) is a medical condition characterized by an abnormally high level of homocysteine (Hcy) in the blood. Homocysteine is a toxic sulfur-containing amino acid that is produced during the metabolism of methionine. Under normal circumstances, Hcy is recycled back to methionine via the remethylation pathway, through the action of various enzymes and vitamins, particularly folic acid (vitamin B9) and B12 used when intracellular methionine levels are low, thus restoring the necessary levels to correctly maintain active protein synthesis. A second pathway, used in cases of intracellular methionine excess, (the trans-sulfuration pathway) is the one that recycles Hcy into cysteine (a precursor of glutathione), first passing through cystathionine (via the enzyme cystathionine beta-synthase), a reaction that requires vitamin B6 in its active form. HHcy has been identified as a risk factor for a variety of disorders, including cardiovascular diseases, multiple sclerosis, diabetes, Alzheimer's and Parkinson's diseases, osteoporosis and cancer. However, it remains unclear whether the slightly elevated concentration of Hcy (Hcy 7-10 μmol/L) is a causative factor or simply a marker of these pathologies. In human plasma, the concentration of Hcy ([Hcy]) is classified as mild (15 to 30 μmol/L), moderate (30 to 100 μmol/L), and severe (greater than 100 μmol/L). Interestingly, many laboratories continue to consider 25 μmol/L as normal. This review seeks to examine the controversial literature regarding the normal range of HHcy and emphasizes that even a [Hcy] level of 10 μmol/L may contribute to the development of several diseases, aiming to discuss whether it would be appropriate to lower the threshold of HHcy normal values.

Frailty Is Associated with Malnutrition-Inflammation Syndrome in Older CKD Patients

Patients affected by chronic kidney disease (CKD) are generally considered to be frailer than those with preserved renal function. We cross-sectionally evaluated the associations between frailty, malnutrition-inflammation syndrome and circulating inflammatory cytokines in 115 older individuals with advanced CKD. As for frailty definition, we adopted Fried's frailty phenotype (FP), while malnutrition-inflammation syndrome was assessed using the Malnutrition-Inflammation Score (MIS) and circulating inflammatory cytokines (IL-6; TNFα; MCP-1). A total of 48 patients were frail, and mean eGFR was comparable in both frail and non-frail patients (24 ± 10 vs. 25 ± 11 mL/min/1.73 m2; p = 0.63). Frail patients had higher MIS (6 [4-11] vs. 4 [3-5]; p < 0.0001) but cytokine concentrations were comparable in both groups. At multivariate regression, FP was independently associated with MIS, age, gender and pre-albumin but not with cytokines. However, we found some associations between inflammatory cytokines and some specific frailty criteria: weight loss and slowness were associated with MCP-1 (respectively p = 0.049 and p < 0.0001) and weakness with IL-6 (p = 0.005); in conclusion, in older patients with advanced CKD, frailty is strictly associated with malnutrition-inflammation syndrome but not with circulating inflammatory cytokines.

Relationship between Prognostic Nutritional Index and Amputation in Patients with Diabetic Foot Ulcer

The prognostic nutritional index (PNI) is a new marker used to assess a patient's nutritional and immune status. It is calculated using serum albumin levels and total lymphocyte count. The aim of this study was to investigate the relationship between PNI and amputation in patients with diabetic foot ulcer (DFU). Patients with DFU were enrolled in this retrospective study. In our study, a total of 386 patient data, of 110 (28.5%) amputated and 276 (71.5%) non-amputated patients, were statistically analyzed. PNI values were significantly lower in the amputated patient group than in the non-amputee patient group (p < 0.001). According to the ROC analysis results, PNI was significant in the prediction of amputation at an excellent level (AUC = 0.937 (0.911-0.963), p < 0.001). The optimal cut-off point for PNI was found to be 39,005. There was classification success for this cut-off point: sensitivity was calculated as 82.7% (74.1-89) and specificity as 93.1% (89.3-95.7). In the multivariate model, the odds ratio (OR) (95% CI) was calculated as 81.8 (38.5-173.7) for PNI. The PNI was associated with an increase in amputation rate in patients with DFU. By using PNI, patients can be directed to advanced centers and have access to early and appropriate interventions.

Unveiling the Hidden Burden: Estimating All-Cause Mortality Risk in Older Individuals with Type 2 Diabetes

Background

The mortality rate among older persons with diabetes has been steadily increasing, resulting in significant health and economic burdens on both society and individuals. The objective of this study is to develop and validate a predictive nomogram for estimating the 5-year all-cause mortality risk in older persons with T2D (T2D).

Methods

We obtained data from the National Health and Nutrition Survey (NHANES). A random 7 : 3 split was made between the training and validation sets. By linking the national mortality index up until December 31, 2019, we ensured a minimum of 5 years of follow-up to assess all-cause mortality. A nomogram was developed in the training cohort using a logistic regression model as well as a least absolute shrinkage and selection operator (LASSO) regression model for predicting the 5-year risk of all-cause mortality. Finally, the prediction performance of the nomogram is evaluated using several validation methods.

Results

We constructed a comprehensive prediction model based on the results of multivariate analysis and LASSO binomial regression. These models were then validated using data from the validation cohort. The final model includes four independent predictors: age, gender, estimated glomerular filtration rate, and white blood cell count. The C-index values for the training and validation cohorts were 0.748 and 0.762, respectively. The calibration curve demonstrates satisfactory consistency between the two cohorts.

Conclusions

The newly developed nomogram proves to be a valuable tool in accurately predicting the 5-year all-cause mortality risk among older persons with diabetes, providing crucial information for tailored interventions.

In Patients with Chronic Kidney Disease Advanced Glycation End-Products Receptors Isoforms (sRAGE and esRAGE) Are Associated with Malnutrition

Background: in patients with chronic kidney disease (CKD), the inflammatory and pro-oxidant milieu may contribute to malnutrition development. In this study, we investigated the relationship between inflammation, advanced glycation end-products (AGEs), and their receptors (RAGEs) with malnutrition in CKD patients. Methods: we evaluated 117 patients. AGEs were quantified by fluorescence intensity using a fluorescence spectrophotometer, soluble RAGEs isoforms, and inflammatory interleukins by ELISA. Malnutrition was assessed by a malnutrition inflammation score. Results: mean age was 80 ± +11 years, eGFR was 25 ± +11 mL/min/1.73 m2 and BMI was 28 ± 5 Kg/m2. Malnourished individuals were older, had lower estimated protein intake (nPCR 0.65 ± 0.2 vs. 0.8 ± 0.2 vs. 0.8 ± 0.3, p = 0.01), higher C reactive protein (CRP 0.6 ± 1 vs. 0.6 ± 0.7 vs. 0.17 ± 0.13, p = 0.02) and tumor necrosis factor α (TNF α 14.7 ± 8.7 vs. 15.6 ± 8 vs. 11.8 ± 5.8, p = 0.029). Malnourished patients had higher sRAGE (2813 ± 1477 vs. 2158 ± 1236 vs. 2314 ± 1115, p = 0.035) and esRAGE (648 [408–1049] vs. 476 [355–680] vs. 545 [380–730] p = 0.033). In the multivariate analysis, only sRAGE maintained its association with malnutrition (p = 0.02) independently of aging and inflammation. Conclusions: in CKD patients, RAGEs isoforms, but not AGEs, are associated with malnutrition, irrespective of systemic inflammation, aging, and renal function.

Effects of Expanded Hemodialysis with Medium Cut-Off Membranes on Maintenance Hemodialysis Patients: A Review

Kidney failure is associated with high morbidity and mortality. Hemodialysis, the most prevalent modality of renal replacement therapy, uses the principle of semipermeable membranes to remove solutes and water in the plasma of patients with kidney failure. With the evolution of hemodialysis technology over the last half century, the clearance of small water-soluble molecules in such patients is adequate. However, middle molecules uremic toxins are still retained in the plasma and cause cardiovascular events, anemia, and malnutrition, which significantly contribute to poor quality of life and high mortality in maintenance hemodialysis patients. A new class of membrane, defined as a medium cut-off (MCO) membrane, has emerged in recent years. Expanded hemodialysis with MCO membranes is now recognized as the artificial kidney model closest to natural kidney physiology. This review summarizes the unique morphological characteristics and internal filtration–backfiltration mechanism of MCO membranes, and describes their effects on removing uremic toxins, alleviating inflammation and cardiovascular risk, and improving quality of life in maintenance hemodialysis patients.

Cardiovascular Risk Markers in Hemodialysis Patients

Cardiovascular events are the main cause of death in hemodialysis patients. Nevertheless, acute myocardial infarction may be misdiagnosed in uremic patients, because typical markers have a high rate of false positivity. A recent two-year prospective study showed that predialytic high serum concentrations of troponin T and CK-MB mass were associated with high mortality, cardiac mortality, myocardial infarction and unstable angina (MACEs). We studied 16 uremic patients (13 M; 3 W) on standard HD and 6 patients (4 M; 2 W) on on-line HDF, who had been taking folic acid for at least three months. Patients who suffered from acute or chronic cardiac ischemic disease were excluded. Anthropometric parameters, pre and post-dialytic pH, HCO3 and electrolytes did not differ between the two groups. Kt/V and URR % were lower in conventional HD vs on-line HDF (p<0.04; p<0.04). ORR % was strongly elevated in on-line HDF compared with HD (p<0.005). In conventional HD, ORR % was directly correlated with Kt/V and URR% (r = 0.49, p<0.04; r = 0.48, p<0.04, respectively). Even in on-line HDF ORR % was directly correlated with Kt/V and URR % (r = 0.79, p<0.04; r = 0.76, p<0.05, respectively). Troponin I and CK-MB mass were not significantly different in pre vs post-dialysis, both in standard HD and on-line HDF. Nevertheless, in standard HD postdialytic troponin I correlated with serum sodium concentration (r = 0.93, p < 0.000), potassium (r = 0.67, p < 0.004) and serum chlorine (r = 0.92, p < 0.92, p < 0.000). CK-MB mass showed a correlation with serum chlorine (r = 0.49, p < 0.05). Postdialytic CK-MB mass correlated with serum potassium in on-line HDF (r = 0.83, p < 0.03). Our data suggest that hemodialytic treatments, both standard HD and on-line HDF, do not modify serum troponin I and CK-MB mass. Consequently, we can use these parameters for the diagnostic approach in acute or chronic ischemic heart disease in hemodialysis patients.

Hyperhomocysteinemia in Greyhounds and its Association with Hypofolatemia and Other Clinicopathologic Variables

Background

Folate and cobalamin are essential cofactors for homocysteine (HCY) metabolism. Hyperhomocysteinemia, a multifactorial condition, may reflect B vitamin deficiency and is associated with increased risk of cardiovascular disease, thrombosis, and neurodegenerative and chronic gastrointestinal diseases in humans. Hyperhomocysteinemia has been reported in Greyhounds with suspected chronic enteropathy.

Objectives

To evaluate the frequencies of and the association between hypofolatemia and hyperhomocysteinemia in Greyhounds.

Animals

Data and serum samples from 559 Greyhounds.

Methods

Nested case‐control study. The frequency of hypofolatemia in Greyhounds was determined by a laboratory database search. The relationship between hyperhomocysteinemia (measured by gas chromatography‐mass spectrometry) and hypocobalaminemia and hypofolatemia was evaluated, and its frequency compared between healthy Greyhounds and Greyhounds with thrombosis or chronic diarrhea.

Results

Hypofolatemia was identified in 172 of 423 (41%) Greyhounds and was more common in hypo‐ than in normocobalaminemic dogs (49% vs. 35%; P = .0064). Hyperhomocysteinemia was detected in 53 of 78 (68%) of Greyhounds, being more common in hypo‐ than in normofolatemic dogs (88% vs. 59%; P = .0175). All healthy Greyhounds, 21 of 30 (70%) of dogs with chronic diarrhea and 6 of 8 (75%) of those with thrombosis, were hyperhomocysteinemic. Serum HCY concentrations were inversely correlated with serum folate concentration (ρ = −0.28; P = .0386) and were positively associated with serum albumin concentration (ρ = 0.66; P = .0022).

Conclusions and Clinical Relevance

Hyperhomocysteinemia occurs frequently in the Greyhound population. Its association with hypofolatemia suggests decreased intracellular availability of B vitamins, but the functional implications warrant further investigation. Hyperhomocysteinemia in Greyhounds potentially may serve as a spontaneous canine model to further investigate hyperhomocysteinemia in humans.

High levels of homocysteine downregulate apolipoprotein E expression via nuclear factor kappa B

AIM: To investigate the effect of high homocysteine (Hcy) levels on apolipoprotein E (apoE) expression and the signaling pathways involved in this gene regulation.

METHODS: Reverse transcriptase polymerase chain reaction (RT-PCR) and Western blot were used to assess apoE expression in cells treated with various concentrations (50-500 μmol/L) of Hcy. Calcium phosphate-transient transfections were performed in HEK-293 and RAW 264.7 cells to evaluate the effect of Hcy on apoE regulatory elements [promoter and distal multienhancer 2 (ME2)]. To this aim, plasmids containing the proximal apoE promoter [(-500/+73)apoE construct] alone or in the presence of ME2 [ME2/(-500/+73)apoE construct] to drive the expression of the reporter luciferase gene were used. Co-transfection experiments were carried out to investigate the downstream effectors of Hcy-mediated regulation of apoE promoter by using specific inhibitors or a dominant negative form of IKβ. In other co-transfections, the luciferase reporter was under the control of synthetic promoters containing multiple specific binding sites for nuclear factor kappa B (NF-κB), activator protein-1 (AP-1) or nuclear factor of activated T cells (NFAT). Chromatin immunoprecipitation (ChIP) assay was accomplished to detect the binding of NF-κB p65 subunit to the apoE promoter in HEK-293 treated with 500 μmol/L Hcy. As control, cells were incubated with similar concentration of cysteine. NF-κB p65 proteins bound to DNA were immunoprecipitated with anti-p65 antibodies and DNA was identified by PCR using primers amplifying the region -100/+4 of the apoE gene.

RESULTS: RT-PCR revealed that high levels of Hcy (250-750 μmol/L) induced a 2-3 fold decrease in apoE mRNA levels in HEK-293 cells, while apoE gene expression was not significantly affected by treatment with lower concentrations of Hcy (100 μmol/L). Immunoblotting data provided additional evidence for the negative role of Hcy in apoE expression. Hcy decreased apoE promoter activity, in the presence or absence of ME2, in a dose dependent manner, in both RAW 264.7 and HEK-293 cells, as revealed by transient transfection experiments. The downstream effectors of the signaling pathways of Hcy were also investigated. The inhibitory effect of Hcy on the apoE promoter activity was counteracted by MAPK/ERK kinase 1/2 (MEK1/2) inhibitor U0126, suggesting that MEK1/2 is involved in the downregulation of apoE promoter activity by Hcy. Our data demonstrated that Hcy-induced inhibition of apoE took place through activation of NF-κB. Moreover, we demonstrated that Hcy activated a synthetic promoter containing three NF-κB binding sites, but did not affect promoters containing AP-1 or NFAT binding sites. ChIP experiments revealed that NF-κB p65 subunit is recruited to the apoE promoter following Hcy treatment of cells.

CONCLUSION: Hcy-induced stress negatively modulates apoE expression via MEK1/2 and NF-κB activation. The decreased apoE expression in peripheral tissues may aggravate atherosclerosis, neurodegenerative diseases and renal dysfunctions.

End Stage Renal Disease as a Potential Risk Factor for Retinal Vein Occlusion

End stage renal disease (ESRD) has been reported to be an important risk factor for systemic vascular disease. Retinal vein occlusion (RVO) is closely related with cardiovascular diseases; however, its association with ESRD had not been reported. The aim of the study was to investigate whether ESRD is a risk factor for RVO, including central retinal vein occlusion (CRVO) and branch retinal vein occlusion (BRVO). This population-based study is based on the longitudinal data from Taiwan National Health Insurance Research Database. The study cohort comprised 5344 patients with diagnosis of ESRD on hemodialysis or peritoneal dialysis during the period from January 1996 to December 2011. For each ESRD patient, we selected 20 non-ESRD patients matched on age and sex. Each ESRD patient and his/her controls were followed from the initiation of renal dialysis until either the diagnosis of RVO or censorship. Kaplan-Meier method was used to compare the hazard of RVO between cohorts. Stratified Cox proportional hazard models were applied to estimate the hazard ratio (HR) adjusted by the comorbidities of RVO including diabetes mellitus (DM), hypertension, hypercholesteremia, and hypertriglyceridemia. After stratifying by DM status, the statistics were applied again to examine the associations among the DM cohort and non-DM cohort.The 16-year RVO cumulative incidence for ESRD cohort was 2-fold to the non-ESRD (1.01% vs 0.46%). After matching with age, sex, hypertension, and hypercholesteremia, the adjusted HR was 1.46 (95% confidence interval = 1.07-2.01, P value = 0.018). By further excluding patients with DM, the adjusted HR escalated to 2.43 (95% confidence interval = 1.54-3.83, P < 0.001). In contrast, there was no significant risk of ESRD on RVO in the DM patients (HR = 1.03). We conclude that among the non-DM patients, ESRD cases had significantly higher RVO rate than the non-ESRD, which indicates that ESRD maybe a potential risk factor for the development of RVO in nondiabetic patients.

Triglyceride to high-density lipoprotein cholesterol ratio predicts cardiovascular outcomes in prevalent dialysis patients

Triglyceride to high-density lipoprotein cholesterol (TG/HDL-C) ratio, an indicator of atherogenic dyslipidemia, is a predictor of cardiovascular (CV) outcomes in the general population and has been correlated with atherosclerotic events. Whether the TG/HDL-C ratio can predict CV outcomes and survival in dialysis patients is unknown. We performed this prospective, observational cohort study and enrolled 602 dialysis patients (539 hemodialysis and 63 peritoneal dialysis) from a single center in Taiwan followed up for a median of 3.9 years. The outcomes were the occurrence of CV events, CV death, and all-cause mortality during follow-up. The association of baseline TG/HDL-C ratio with outcomes was explored with Cox regression models, which were adjusted for demographic parameters and inflammatory/nutritional markers. Overall, 203 of the patients experienced CV events and 169 patients died, of whom 104 died due to CV events. Two hundred fifty-four patients reached the composite CV outcome. Patients with higher TG/HDL-C levels (quintile 5) had a higher incidence of CV events (adjusted hazard ratio [HR] 2.03, 95% confidence interval [CI] 1.19-3.47), CV mortality (adjusted HR 1.91, 95% CI 1.07-3.99), composite CV outcome (adjusted HR 2.2, 95% CI 1.37-3.55), and all-cause mortality (adjusted HR 1.94, 95% CI 1.1-3.39) compared with the patients in quintile 1. However, in diabetic dialysis patients, the TG/HDL-C ratio did not predict the outcomes. The TG/HDL-C ratio is a reliable and easily accessible predictor to evaluate CV outcomes and survival in prevalent nondiabetic dialysis patients. ClinicalTrials.gov: NCT01457625.

Diabetes in rural individuals of different nutritional status and the alarming situation demands focus more on its under-nutrition association

OBJECTIVE

To study the relationship of nutritional-status with diabetes.

DESIGN

The socioeconomics/anthropometrics, blood-glucose/systemic-hypertension are evaluated in consecutively-selected diabetic-patients.

SETTING

Semi-urban/rural India.

SUBJECTS

Hyperglycaemic patients (total 90/male 37).

RESULTS

Blood-glucose (PP-mean ± SE) in individuals is overweight - 38.89% (226.94 ± 9.59), normal-weight - 50% (217.58 ± 1.34), underweight - 11.11% (305.50 ± 21.35) indicating most hyperglycaemia in undernourished-group (F = 6.357, p < 0.003). This group occupies higher glucose-groups in ≤140, 141-270, and ≥270 mg/dL. The blood-glucose negatively correlates with waist(r = -0.282; p < 0.01) and hip (r = -0.254; p < 0.05) circumference indicating the under-nutrition association with glucose-homeostasis (F = 7.6-8.2, p < 0.001). The higher glucose is noticed in more number of individuals in lower (<40 years) age-group (χ(2 )= 12.86; p < 0.002/ρ = -0.355; p < 0.001). The prevalence of hypertension is 28% (underweight = 20%, overweight = 27%, normal = 30%). The group of 141-270 mg/dL glucose has 45% and rest groups together have 23% hypertensive individuals relating directly, hypertension and diabetic-onset.

CONCLUSIONS

Diabetes, explored in <40 years group and even more in female should be extensively studied accounting WHO categorization (1985/TRS/727) of malnutrition related diabetes (MRDM). Further, different interactive risk-factors should be properly addressed and the global-malnutrition/gender-based inequities be eradicated.

[The degree of chronic renal failure is associated with the rate of pro-inflammatory cytokines, hyperhomocysteinemia and with oxidative stress]

AIM

To evaluate pro-inflammatory cytokines, homocysteinemia and markers of oxidative status in the course of chronic renal failure.

PATIENTS AND METHODS

One hundred and two patients (male/female: 38/64; age: 45±07 years) with chronic renal failure were divided into 4 groups according to the National Kidney Foundation classification. They included 28 primary stage renal failure patients, 28 moderate stage renal failure, 28 severe stage renal failure and 18 end stage renal failure. The inflammatory status was evaluated by the determination of pro-inflammatory cytokines (tumor necrosis factor-α, interleukin-1β, interleukin-6) and total homocysteine. Pro-oxidant status was assessed by assaying thiobarbituric acid reactive substances, hydroperoxides, and protein carbonyls. Antioxidant defence was performed by analysis of superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase.

RESULTS

Inflammatory markers were elevated in the end stage renal failure group compared to the other groups (P<0.001). Indeed, an increase in thiobarbituric acid reactive substances, hydroperoxides and protein carbonyls was noted in the end stage renal failure group in comparison with the other groups (P<0.001), while the levels of antioxidants enzymes activity were decreased in the study population (P<0.001).

CONCLUSION

Impaired renal function is closely associated with the elevation of inflammatory markers leading to both increased markers of oxidative stress and decreased antioxidant defense.

Inflammatory status in chronic renal failure: The role of homocysteinemia and pro-inflammatory cytokines

AIM: To evaluate determinants of inflammatory markers in chronic renal failure patients according to the level of glomerular filtration rate.

METHODS: One hundred fifty four patients (Age: 44 ± 06 years; male/female: 66/88) with chronic renal failure (CRF) were divided into 6 groups according to the National Kidney Foundation (NKF) classification. They included 28 primary stage renal failure patients (CRF 1), 28 moderate stage renal failure patients (CRF 2), 28 severe stage renal failure patients (CRF 3), 18 end-stage renal failure patients (CRF 4), 40 hemodialysis (HD) patients, and 12 peritoneal dialysis (PD) patients. Tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6) and C-reactive protein (CRP) were analyzed by immunosorbent assay kit (ELISA) (Cayman Chemical’s ACETM EIA kit). Immunoassay methods were used for total homocysteine (tHcy) (fluorescence polarization immunoanalysis HPLC, PerkinEmer 200 series), transferrin (MININEPHTM human transferin kit: ZK070.R), ferritin (ADVIA Centaur) and fibrinogen analysis (ACL 200). Differences between groups were performed using SPSS 20.0 and data are expressed as the mean ± SD.

RESULTS: Results showed that in comparison with CRF 1 group and other groups, TNF-α and IL-6 levels were respectively more elevated in HD (16.38 ± 5.52 pg/mL vs 0.39 ± 0.03 pg/mL, 11.05 ± 3.59 pg/mL vs 8.20 ± 0.22 pg/mL, P < 0.001) and PD (14.04 ± 3.40 pg/mL vs 0.39 ± 0.03 pg/mL, 10.15 ± 1.66 pg/mL vs 8.20 ± 0.22 pg/mL, P < 0.001). IL-1β levels were increased in HD (9.63 ± 3.50 pg/mL vs 3.24 ± 0.10 pg/mL, P < 0.001) and CRF 4 (7.76 ± 0.66 pg/mL vs 3.24 ± 0.10 pg/mL, P < 0.001) patients than in CRF 1 and in the other groups. Plasma tHcy levels were higher in HD (32.27 ± 12.08 μmol/L) and PD (28.37 ± 4.98 μmol/L) patients compared to the other groups of CRF (P < 0.001). The serum CRP level was significantly increased in HD (18.17 ± 6.38 mg/L) and PD (17.97 ± 4.85 mg/L) patients compared to the other groups of CRF patients (P < 0.001). The plasma fibrinogen level was more elevated in HD (6.86 ± 1.06 g/L) and CRF 4 (6.05 ± 0.57 g/L) than in the other groups (P < 0.001). Furthermore; the ferritin level was higher in HD (169.90 ± 62.16 ng/mL) and PD (90.08 ± 22.09 ng/mL) patients compared to the other groups of CRF (P < 0.001). The serum transferrin value was significantly decreased especially in PD (1.78 ± 0.21 g/L) compared to the other groups (P < 0.001). We found a negative correlation between glomerular filtration rate (GFR), TNF-α levels (r = -0.75, P < 0.001), and tHcy levels (r = -0.68, P < 0.001). We observed a positive correlation between GFR and transferrin levels (r = 0.60, P < 0.001).

CONCLUSION: CRF was associated with elevated inflammatory markers. The inflammation was observed at the severe stage of CRF and increases with progression of renal failure.

Dietary antioxidant capacity is associated with improved serum antioxidant status and decreased serum C-reactive protein and plasma homocysteine concentrations

PURPOSE

To investigate the associations of dietary TAC from diet and supplements with serum antioxidant concentrations and serum C-reactive protein (CRP) and plasma total homocysteine (tHcy) in US adults.

METHODS

This was a cross-sectional study. Food consumption data, serum antioxidant levels, and serum CRP and Plasma tHcy concentrations of 4,391 US adults aged ≥19 years in the National Health and Nutrition Examination Survey 2001-2002 were analyzed. The USDA flavonoid and proanthocyanidin databases and dietary supplement data as well as antioxidant capacities of 43 antioxidants were also utilized.

RESULT

Serum CRP and plasma tHcy concentrations were higher in older adults, smokers, and those with lower non-leisure time physical activity levels (P < 0.05). Energy-adjusted daily total antioxidant capacity (TAC) from diet and supplements was positively associated with serum vitamin E and carotenoid concentrations (P < 0.05). Adjusted odds ratio (OR) for plasma tHcy >13 μmol/L significantly decreased across quartiles of TAC from diet and supplements (Q1 = 2.18 (1.56-2.77); Q2 = 1.30 (1.00-2.07); Q3 = 1.34 (0.84-2.28); Q4 = 1.00; P for linear trend <0.001). A negative trend across quartiles of TAC from diet and supplements was also observed in OR for serum CRP ≥3 mg/L (Q1 = 1.26 (0.97-1.70); Q2 = 1.21 (0.91-1.66); Q3 = 0.97 (0.80-1.24); Q4 = 1.00; P for linear trend <0.05).

CONCLUSIONS

These findings indicated that dietary TAC provided an integrated conceptual tool in assessing serum antioxidants and investigating the associations between antioxidant intake and CVD risk. The implicated applicability of dietary TAC needs further validation in prospective cohort studies.

What is the meaning of homocysteine in patients on dialysis?

OBJECTIVE

To evaluate the determinants of total plasma homocysteine levels and their relations with nutritional parameters, inflammatory status, and traditional risk factors for cardiovascular disease in renal failure patients on dialysis treatment.

DESIGN

The study was conducted on 70 clinically stable patients, 50 of them on hemodialysis (70% men; 55.3 ± 14.5 years) and 20 on peritoneal dialysis (50% men; 62 ± 13.7 years). Patients were analyzed in terms of biochemical parameters (serum lipids, creatinine, homocysteine [Hcy], creatine-kinase [Ck], folic acid, and vitamin B(12)), anthropometric data, markers of inflammatory status (tumor necrosis factor-alpha, C-reactive protein, interleukin-6), and adapted subjective global assessment.

RESULTS

The total prevalence of hyperhomocysteinemia (>15 μmol/L) was 85.7%. Plasma folic acid and plasma vitamin B(12) were within the normal range. Multiple regression analysis (r(2) = 0.20) revealed that the determinants of total Hcy were type of dialysis, creatinine, Ck, folic acid, and total cholesterol. Hcy was positively correlated with albumin and creatinine and negatively correlated with total cholesterol, high density lipoprotein cholesterol, folic acid, and vitamin B(12).

CONCLUSIONS

The determinants of total Hcy in the study sample were type of dialysis, creatinine, Ck, folic acid, and total cholesterol. Evidently, the small sample size might have had an effect on the statistical analyses and further studies are needed. However, Hcy in patients on dialysis treatment may not have the same effect as observed in the general population. In this respect, the association between malnutrition and inflammation may be a confounding factor in the determination of the true relationship between Hcy, nutritional status, and cardiovascular risk factors in this group.

Inflammation and oxidative stress in end-stage renal disease patients treated with hemodialysis or peritoneal dialysis

PURPOSE

The impact of different dialysis modalities on oxidative stress and inflammation and the factors implicated in this interrelationship have not been adequately studied. This study was designed to comparatively evaluate the effect of hemodialysis (HD) and peritoneal dialysis (PD) on oxidative stress and inflammatory biomarkers and to search for associated factors.

METHODS

We studied 20 HD, 11 PD patients and 11 healthy controls. Calculations were based on total antioxidant capacity (TAC) and superoxide dismutase (SOD), by spectrophotometry, as oxidative stress biomarkers; and high sensitivity CRP (hs-CRP), Interleukin-6 (IL-6) and Tumor Necrosis Factor-alpha (TNF-alpha), by ELISA, as inflammation biomarkers.

RESULTS

HD and PD patients showed significantly increased levels of TA C, SOD and hs-CRP compared to healthy controls. No significant difference was observed in TNF-alpha and IL-6. Compared to HD patients, PD patients showed TNF-alpha levels that were increased, although non-significantly, and significantly higher homocysteine (Hcy). No differences were observed for IL-6, hs-CRP, TA C and SOD. In HD patients, significant positive correlations were found between intact parathyroid hormone (iPTH) and TNF-alpha, and between uric acid (UA) and TAC. Beta2-microglobulin (Beta2M) was negatively correlated with TAC, total cholesterol (TC) positively with TNF-alpha and negatively with SOD, and triglycerides (TG) correlated positively with TNF-alpha. In PD patients, TG correlated positively with TNF-alpha, HDL-cholesterol negatively with TNF-alpha, LDL-cholesterol negatively with SOD, and Beta2M negatively with SOD.

CONCLUSIONS

HD and PD patients show similar degrees of inflammation and oxidative stress activation. Factors such as UA, iPTH, Beta2M and lipid profile correlate to oxidative stress and inflammatory biomarkers in both HD and PD patients.

Cardiovascular risk factors in hemodialysis and peritoneal dialysis patients

BACKGROUND

Cardiovascular disease (CVD) is the major cause of mortality and morbidity of hemodialysis (HD) and peritoneal dialysis (CAPD) patients. We aimed to investigate the cardiovascular risk factors and their correlation with CVD in groups of HD and CAPD patients.

METHODS

Thirty HD patients, 30 CAPD patients and 30 healthy controls were included in the study. Apolipoprotein A-l (apo A-l), apolipoprotein B (apo B), apolipoprotein(a) [Lp(a)] and high-sensitivity CRP (hs-CRP) were measured with a Beckman Coulter nephelometer, and homocysteine (Hcy) was determined with an Agilent HPLC analyzer. Lipid profile was determined with a Synchron LX 20 Pro analyzer.

RESULTS

Hcy levels were 41.9+/-19.4, 41.8+/-38.5 and 9.3+/-3.5 micromol/L; Lp(a) levels were 325+/-315, 431+/-367 and 130+/-97 mg/L; hs-CRP levels were 3.78+/-3.21, 4.34+/-3.39 and 2.07+/-1.67 mg/L; apo A1/apo B ratios were 1.46+/-0.6, 1.36+/-0.5 and 1.80+/-0.59; total cholesterol levels were 3.56+/-0.7, 4.84+/-1.1 and 4.39+/-0.5 mmol/L; triglycerides were 1.44+/-0.5, 1.60+/-0.8 and 0.85+/-0.5 mmol/L in the HD, CAPD and control groups, respectively.

CONCLUSION

HD and CAPD patients had higher Hcy, hs-CRP and Lp(a) levels and lower apo A/B ratios than controls. There was no significant difference between the HD and CAPD groups. Hypertension, age and hs-CRP showed a positive correlation with CVD.

The influence of fruit and vegetable intake on the nutritional status and plasma homocysteine levels of institutionalised elderly people

OBJECTIVE

To determine the difference in the nutritional status of elderly people depending on their consumption of fruits and vegetables, and to study the possible association between the consumption of these foods and different cardiovascular risk factors, especially total plasma homocysteine (t-Hcys) levels.

DESIGN, SETTING AND SUBJECTS

A cross-sectional study in 152 institutionalised older people from Madrid aged > or = 65 years. Food and nutrient intakes were recorded over 7 days using the 'precise individual weighing' method. The weight, height, and waist and hip circumferences of all subjects were recorded, as were their alpha-erythrocyte glutathione reductase, serum B6, B12 and folate levels, erythrocyte folate levels, t-Hcys levels, serum lipids and blood pressure. The experimental population was then divided into tertiles depending on the serving intake of fruit and vegetables (T1, < 2.29 servings day(-1); T2, 2.29-2.79 servings day(-1); and T3, >2.79 servings day(-1)).

RESULTS

Compared with T1 subjects, T3 subjects showed consumptions of cereals, pulses, meat, fish and eggs closer to those recommended (P < 0.05). In addition, the contribution of their diet towards covering the recommended daily intake of vitamin B1, niacin, vitamin B6, folic acid, vitamin C, B12, vitamin A, and P, Mg, Zn and Fe was higher. The intake of fibre increased with consumption of fruit and vegetables (r = 0.6839, P < 0.001). T3 subjects also had better serum and erythrocyte folate levels than T1 and T2 subjects (P < 0.05). A positive correlation was found between the consumption of fruit and vegetables and serum folate (r = 0.2665, P < 0.01) and with erythrocyte folate levels (r = 0.2034, P < 0.05), and a negative correlation with t-Hcys (r = -0.2493, P < 0.01).

CONCLUSIONS

Greater consumption of fruit and vegetables is associated with better food habits, increased vitamin and mineral intakes and lower t-Hcys levels. Considering that the fruit and vegetable intake in Spanish elderly people is very low, it is recommended that the consumption of fruits and vegetables by elderly people be increased.

Homocysteine levels are associated with increased risk of congestive heart failure in patients with and without coronary artery disease

BACKGROUND

Increased homocysteine (HCY) is associated with increased risk of vascular disease. Whether HCY affects development of congestive heart failure (CHF) independent of coronary artery disease (CAD) is uncertain. We evaluated whether increased HCY predicts low ejection fraction or clinical CHF.

METHODS

Patients (n = 2,842) undergoing coronary angiography had HCY measured between 1994 and 1999 and were prospectively studied. Left ventricular dysfunction (LVD) was defined as ejection fraction < or =40%. Multivariable regressions assessed predictive strength of HCY for LVD or LVD/CHF.

RESULTS

The average age was 64 +/- 12 years; 69% were men, and 74% had CAD. LVD was present in 12% and the combination of either LVD or clinical CHF was present in 21.9%. Quartiles of HCY were: < or =10.5 (Q1), 10.5-13.2 (Q2), 13.3-17.0 (Q3) and > or =17.1 micromol/l (Q4). LVD and LVD/CHF were more prevalent in Q3 (15, 25%) and Q4 (15, 27%) than in Q1 HCY (8.4, 18%; p < 0.001 vs. Q4). After adjustment, Q3 and Q4 HCY independently predicted LVD (OR = 1.7, 95% CI 1.2-2.5, p = 0.004; OR = 1.8, 95% CI 1.3-2.6, p = 0.002) or LVD/CHF (OR = 1.4, 95% CI 1.04-1.8, p = 0.03; OR = 1.7, 95% CI 1.3-2.2, p < 0.001). Findings did not differ by disease etiology: for Q4 among non-CAD patients, OR = 1.7 for LVD and OR = 1.7 for LVD/CHF. Further, there was no interaction of results with gender.

CONCLUSION

High HCY levels (Q3/4 > or =13.3 micromol/l) are associated with LVD and combined endpoint of LVD/clinical CHF. This relationship is independent of CHF etiology and gender. Further research is indicated to distinguish between a causal or noncausal mechanism for this association.

Clinical significance of homocysteine in elderly hospitalized patients

Serum homocysteine levels, which increase with age, are now recognized as a vascular risk factor and are related to the development of heart failure and dementia in the elderly. However, relatively low serum homocysteine levels have also been reported to be an adverse prognostic factor in dialysis patients. The objective of the study was to analyze the prevalence, clinical significance, and prognostic value of serum homocysteine levels in patients older than 65 years, admitted to a general internal medicine hospitalization unit. We studied 337 hospitalized patients, 184 males and 153 females, aged 77.2+/-0.4 years, whose admission was not determined by an acute vascular event. We recorded past vascular events and vascular risk factors. We determined the body mass index (weight in kilograms divided by the square of height in meters), and cholesterol, triglyceride, folate, vitamin B12, and homocysteine levels. We also studied 36 control subjects (18 males and 18 females) of similar age. After discharge, we assessed the survival status of 301 patients by telephone recall. Survival curves were plotted by the method of Kaplan and Meier. Median survival was 1186 days. The 15th (9.6 micromol/L) and 50th (14.4 micromol/L) percentiles, as the lowest and highest cut-off points, were empirically defined as those related to a shorter survival. Serum homocysteine concentration was significantly positively correlated with age and serum creatinine and albumin concentrations, and negatively correlated with serum cobalamin and folate concentrations. The average serum homocysteine concentration for the patients group, as a whole, was 16.5+/-0.5 micromol/L, not significantly different from the control group, but with a much greater dispersion, as patients with congestive heart failure or cognitive impairment had higher serum homocysteine concentrations, and patients with sepsis, leukocytosis, and hypoalbuminemia had lower concentrations. Malnutrition was associated both with abnormally high and low homocysteine concentrations, and abnormally low and abnormally high homocysteine concentrations were both associated with higher mortality. In conclusion, low homocysteine levels in elderly non-vitamin-supplemented hospitalized patients should not be interpreted as a protective factor in some individuals. Instead, it may be considered as an effect of an inflammatory-malnutrition process associated with a poor prognosis.

Total homocysteine concentration and associated cardiovascular and renal implications in adults

Hyperhomocysteinemia has been linked to an increased risk for cardiovascular (CV) disease since 1969. Recent epidemiological and cohort observations continue to confirm this relationship, provided the homocysteine concentration is elevated. This elevation in homocysteine concentration and increased CV disease risk are particularly strong in patients with renal disease. Hyperhomocysteinemia is also related to declining status of vitamins B6 and B12, folate, and in some cases riboflavin. This relationship between vitamins and homocysteine concentration has provided the basis for clinical trials targeting CV risk reduction by vitamin supplementation. This review describes the evidence behind vitamin supplementation as it pertains to homocysteine status and make recommendations for vitamin intake management in patients with hyperhomocysteinemia, including those patients with renal disease.

Association of serum albumin and homocysteine levels and cardio-ankle vascular index in patients with continuous ambulatory peritoneal dialysis

BACKGROUND

The cardio-ankle vascular index (CAVI) is a newly developed arteriosclerotic measurement that has been proposed as an alternative to aortic pulse-wave velocity (PWV). The present study used the CAVI to identify the main factors associated with arteriosclerosis in continuous ambulatory peritoneal dialysis (CAPD) patients.

METHODS

Fifteen CAPD patients were enrolled in the study. The CAVI is independent of the pressure and vascular reflection between the heart valve and the ankle. Serum albumin, uric acid, total calcium, phosphorus, lipid levels, high-sensitivity C-reactive protein and homocysteine concentrations in CAPD patients were measured using standard methods. Total body fat mass, truncal and non-truncal fat mass and lean body mass were measured using dual energy X-ray absorptiometry with a Lunar DPX-L scanner.

RESULTS

CAPD patients had a mean CAVI of 9.37 +/- 3.16 m/sec, which was higher than the general population. The CAVI was negatively correlated with the serum albumin concentration (r=-0.548; p=0.034). Stepwise regression analysis showed that both the serum albumin concentration (beta=-0.643, p=0.013) and the serum homocysteine level (beta=0.486, p=0.004) were independently associated with the CAVI.

CONCLUSIONS

An increase in CAVI was independently associated with both serum albumin and homocysteine level.

Factors involved in baseline hyperhomocysteinemia in renal transplantation

Hyperhomocysteinemia (hyperHcy) is one cardiovascular risk. The objective of this study was to establish the prevalence demographic, and clinical and analytical factors related to hyperhomocysteinemia among renal transplant patients. The mean Hcy level was 17.3 micromol/L; the prevalence of hyperHcy was 61.2%. The population was categorized as hyperHcy and normal-homocysteinemia (Hcy) patients. Those subjects with hyperHcy were mostly men, with lower intraerythrocyte folate and vitamin B(12) levels, higher fibrinogen levels, and poorer renal function. Multivariate evaluation showed that creatinine clearance, plasma intraerythrocyte folate and vitamin B(12) levels, and plasma fibrinogen levels were independently associated with Hcy levels. Even though the Hcy level was slightly higher among patients who suffered a posttransplantation cardiovascular event, this was statistically significant.

Homocysteine in chronic kidney disease: Effect of low protein diet and repletion with B vitamins

BACKGROUND

Data are limited on the determinants of homocysteine (tHcy) and its relationship with nutritional indices, and dietary protein intake, in the earlier stages of chronic kidney disease (CKD).

METHODS

Levels of tHcy were assayed at baseline (N= 804) and 1 year postrandomization (N= 678) in the Modification of Diet in Renal Disease (MDRD) Study [study A, glomerular filtration rate (GFR) 25 to 55 mL/min/1.73 m(2) and study B GFR 13 to 24 mL/min/1.73 m(2)]. Participants were randomly assigned to different blood pressure targets and protein diets and all subjects received a multivitamin supplement containing 1 mg of folic acid, 10 mg pyridoxal 5'-phosphate (PLP) and 6 mug of vitamin B(12). Multivariable analyses were used to evaluate determinants of tHcy at baseline and 1 year.

RESULTS

The prevalence of hyperhomocysteinemia (tHcy >15 mumol/L) at baseline was 56% in study A and 85% in study B. Baseline tHcy was negatively correlated with measures of body fat and dietary protein intake. Folate, vitamin B(12), and GFR were the major determinants of tHcy levels. Of the patients with hyperhomocysteinemia at baseline, 49% and 24% reduced their tHcy levels at 1 year to < or =15 micromol/L in study A and study B, respectively. There was no association between dietary protein intake and odds of developing hyperhomocysteinemia at 1 year in study A (P= 0.94) or study B (P= 0.10).

CONCLUSION

Hyperhomocysteinemia is partly amenable to correction by vitamin supplementation in CKD stages 3 and 4. There is insufficient evidence to suggest that low tHcy is associated with poor nutritional status in the MDRD Study cohort. B vitamins and GFR, but not dietary protein, are the major determinants of tHcy in this patient population.

Diabetes mellitus, hyperhomocystinemia and atherosclerotic vascular disease in Taiwanese chronic hemodialysis patients: a retrospective study

AIM

Diabetic patients with hemodialysis (HD) have a high mortality rate from atherosclerotic vascular disease (ASVD). However, the extent of the role of hyperhomocystinemia as a risk factor of ASVD is uncertain in diabetic HD patients. We investigated whether there was an association with ASVD events in diabetics and non-diabetics where these were chronic hyperhomocystinemia HD patients.

METHODS

Two hundred patients undergoing HD were included in the study. About 50% of the patients had diabetes mellitus (DM). They had predialysis blood work performed for total homocysteine. A history of DM was elicited using information from the patients' questionnaires and verified by careful inpatient and outpatient chart review.

RESULTS

A total of 196 patients had hyperhomocystinemia and were enrolled this study. Mean homocysteine concentration was 29.7 +/- 6.6 micromol/L overall. DM was present in 50.0% of patients. The mean homocysteine concentration was 29.4 +/- 9.5 micromol/L and 29.9 +/- 9.7 micromol/L in diabetic HD patients (n=98) and non-diabetic HD patients (n=98), respectively (P=0.71). There was no association with hyperhomocystinemia between diabetic and non-diabetic in chronic HD patients. There were significant differences including age, sex, HDL cholesterol, triglycerides, hypertension, smoking, serum creatinine, dialysis duration and glucose intolerance in the two groups (P<0.05). There were also significant differences in ASVD (P=0.0027) and CVD (P=0.0017) between diabetics and non-diabetics in cases of chronic hyperhomocystinemia HD patients. The adjusted odds ratio for ASVD was 3.02 (95%CI, 1.63 to 5.59) for those subjects with a DM in the highest quartile compared with the lowest 3 quartiles.

CONCLUSIONS

There were associations with ASVD and CVD in diabetics and non-diabetics in cases of chronic hyperhomocystinemia HD patients. There was no association with hyperhomocystinemia between diabetic and non-diabetic in Taiwanese chronic HD patients. This study found that the presence of DM and advanced age were the major determinants for ASVD events in chronic HD patients, rather than the levels of homocysteine.

Creatine supplementation does not decrease total plasma homocysteine in chronic hemodialysis patients

BACKGROUND

Hyperhomocysteinemia is present in the majority of chronic hemodialysis patients. Treatment with folic acid, vitamin B12, and vitamin B6 cannot fully normalize plasma homocysteine concentrations (tHcy). Previously we have demonstrated the tHcy-lowering effect of creatine supplementation in an animal model of uremia (Kidney Int 64:1331-1337, 2003). The present study investigates the effects of creatine supplementation on tHcy in a vitamin-repleted chronic hemodialysis population.

METHODS

Forty-five hemodialysis patients receiving folic acid and vitamin B6 and B12 were included. Patients were treated with creatine (2 g/day) or placebo during 2 treatment periods of 4 weeks, separated by a washout of 4 weeks. Plasma tHcy, creatine, Kt/V(urea), folic acid, vitamin B12, and routine biochemistry were determined, as well as the prognostic inflammatory and nutritional index.

RESULTS

All patients had elevated tHcy concentrations (21.2 +/- 5.6 micromol/L). Creatine treatment resulted in increased plasma and red blood cell creatine levels, documenting uptake of creatine. Creatine did not affect tHcy concentrations. There was no relationship between plasma creatine concentrations and tHcy concentrations. No changes in body weight, routine biochemistry, nutritional status, folic acid, or vitamin B12 were observed during the study.

CONCLUSION

Creatine supplementation at a rate of 2 g/day does not further decrease tHcy concentrations in chronic dialysis patients already treated with high dose folic acid, vitamin B6, and B12 supplementation.

Malnutrition-inflammation complex syndrome in dialysis patients: causes and consequences

Protein-energy malnutrition (PEM) and inflammation are common and usually concurrent in maintenance dialysis patients. Many factors that appear to lead to these 2 conditions overlap, as do assessment tools and such criteria for detecting them as hypoalbuminemia. Both these conditions are related to poor dialysis outcome. Low appetite and a hypercatabolic state are among common features. PEM in dialysis patients has been suggested to be secondary to inflammation; however, the evidence is not conclusive, and an equicausal status or even opposite causal direction is possible. Hence, malnutrition-inflammation complex syndrome (MICS) is an appropriate term. Possible causes of MICS include comorbid illnesses, oxidative and carbonyl stress, nutrient loss through dialysis, anorexia and low nutrient intake, uremic toxins, decreased clearance of inflammatory cytokines, volume overload, and dialysis-related factors. MICS is believed to be the main cause of erythropoietin hyporesponsiveness, high rate of cardiovascular atherosclerotic disease, decreased quality of life, and increased mortality and hospitalization in dialysis patients. Because MICS leads to a low body mass index, hypocholesterolemia, hypocreatininemia, and hypohomocysteinemia, a "reverse epidemiology" of cardiovascular risks can occur in dialysis patients. Therefore, obesity, hypercholesterolemia, and increased blood levels of creatinine and homocysteine appear to be protective and paradoxically associated with a better outcome. There is no consensus about how to determine the degree of severity of MICS or how to manage it. Several diagnostic tools and treatment modalities are discussed. Successful management of MICS may ameliorate the cardiovascular epidemic and poor outcome in dialysis patients. Clinical trials focusing on MICS and its possible causes and consequences are urgently required to improve poor clinical outcome in dialysis patients.

Plasma C-reactive protein and homocysteine concentrations are related to frequent fruit and vegetable intake in Hispanic and non-Hispanic white elders

Elevated C-reactive protein (CRP) and plasma total homocysteine (Hcy) were recently identified as risk factors for cardiovascular disease. However, few studies have related fruit and vegetable consumption to these markers of inflammation and B vitamin deficiency, particularly in the Hispanic population. We examined the relation of fruit and vegetable intake with plasma CRP and Hcy concentrations in a cross-sectional study. Subjects were 445 Hispanic elders and 154 neighborhood-based non-Hispanic white elders living in Massachusetts. Diet was assessed with a FFQ designed for this population. There were significant inverse dose-response associations between fruit and vegetable intake and plasma CRP (P for trend = 0.010) and Hcy (P for trend = 0.033) concentrations, after adjustment for potential confounders. The prevalence of high plasma CRP (> 10 mg/L), and high Hcy (>10.4 micromol/L for women and >11.4 micromol/L for men), was significantly greater among subjects in the lowest quartile of fruit and vegetable consumption relative to those in the highest quartile, 17.9 vs. 9.1% and 58.7 vs. 44.4%, respectively. With each additional serving of fruit and vegetable intake, adjusted odd ratios for high plasma CRP and Hcy were 0.79 (95% CI: 0.65 to 0.97) and 0.83 (95% CI: 0.72 to 0.96), respectively. Greater frequency of fruit and vegetable intake was associated with significantly lower plasma CRP and Hcy concentrations. Because both of these metabolites are known risk factors for CVD, these findings contribute to the evidence that a higher intake of fruit and vegetables may reduce the risk of CVD.